Cloth shrinking



April 27, 1937.

s. L. CLUETT 2,078,904

CLOTH SHRINKING 5 Sheets-Sheet 1 Filed NOV. 14, 1955 Invalid SargfaralL. CZaett, W Mmk Att ys.

, April 27, 1937. S L CLUETT 2,078,904

CLOTH SHRINKING Filed Nov. 14, 1955 a Sheet s-Sheet 2,

jzzverztai, Sarzfard Z. 5712666,

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April 1937- s. L. CLUETT 2,078,904

CLOTH SHRINKING File'd Nov. 14, 1955 a Shets-Sheet .3

- frzyeizzwy Sanford Z. (724662,

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Patented. Apr. 27, 1937 UNITED STATES PATENT. OFFICE Peabod of New York y 8; 00., Inc., Troy, N. Y., a corporation Application November 14, 1935, Serial No. 49,791'

' 19 Claims. (CI. 26-18.!

This application is a continuation in part of my copending application Serial No. 7,213, filed February 19, 1935.

This invention relates to cloth finishing and more particularly to cloth shrinking machines in which the cloth is compressed endwise by contracting action of a body having elastic properties, for example as illustrated in British Patent No. 400,950 or British Patent No. 402,087

(reprinted as amended). In the latter of these patents there is described a machine in which a thick belt, mainly of rubber and with an inextensible backing, is moved in .a path such that the rubber surface is first convex and relatively 5 extended and then becomes concave and relatively compressed, with consequent shortening of the rubber surface and the cloth which is held in contact therewith. The concave shape of the belt surface may be defined by a guide roll about which the belt passes, and the effective contracting action of the rubber belt surface further increased by driving this guide roll at a faster speed than the belt, thus tending further to stretch the surface portions of the rubber at the point of approach to the roll so as to cause sub sequently an added contracting action by a recoil of these surface portions of the rubber.

The devices of these patents have a high shrinking capacity, which, as indicated above, results from the confinement of the cloth to the rubber surface from a time when the rubber surface is longitudinally stretched until a' time when the rubber surface islongitudinally compressed.

35 I have found that a limitation upon the use of such'machines consists in the tendency of the rubber web-compressing member to exhibit undesirabledistortions in transverse section, in longitudinal section, and in plan, at the place 40 where it is subjected to strong longitudinal compression.

In making thebelt of the British Patent No.

402,087 it has been the practice to build up the inner inextensible layer of the belt about acircular mandrel, then build the thick rubber element about the inextensible layer, producing an endless belt of naturallycircular shape. When that belt has been caused to run around the rolls of the machine, the thick rubber portion has been under heavy lengthwise compression in the region where its web-engaging surface is concave.

Rubber such as that employed in the machines of British Patent No. 402,087 tends strongly to maintain its volume when subjected to compresshrinking-machine, it tends to bulge out sidewise, which has the undesirable effect of pushing 'the fabric web outwardly from its middle toward its selvedges. In addition to causing such lateral deformation of the web as a whole, the sidewise motion of the rubber sometimes results in distorting the warp threads of the fabric into wavy lines.

The sidewise bulging tendency of the rubber component of the belt moreover tends to bend the belt transversely, sorthat, viewed in transverse section, the web-engaging surface of the belt tends to become convex. This convexity may be reduced by the application of sufficient pressure perpendicular to the belt surface, but even when so reduced, there is a greater effective pressure on the web and belt at the middle of the width of the belt which tends to hump up than at the opposite lateral portions which tend to turn down. The tendency is therefore to grip the web more firmly and to shrink the web to a greater extent in its middle than at its selvedges. This irregularity in shrinking is augmented by the fact that the rubber near the edges of the belt can more readily spread sidewise than the rubber in the middle of the belt, and consequently tends to contract the web less in lengthwise direction. Moreover, the necessity for applying heavy pressure to prevent transverse fiexure of the belt involves the application of an undesirably large tension in the relatively inextensible backing element of the belt, and also results in heavy friction losses.

The endwise compression in the rubber, resisted by the relative incompressible nature of the rubber, also results in a tendency for the rubber to pucker or form transverse ridges at the web-engaging surface, thereby tending to impress similar transverse ridges on the web.

The present invention has for its principal object to avoid these difllculties and limitations in the use of elastic web-compressing elements,

sure which must be applied to the web and webcompressing element and thereby permitthe use of smaller and lighter mechanism. Other objects of invention and features of advantage 5 and utility will be apparent from this specification and its accompanying drawings wherein the invention is explained by way of example.

In the drawings, Fig. 1 is a diagrammatic side view of a shrinklO ing machine having the present invention applied thereto;

Fig. 1 is a sectional view on the line I I of Fig. 1 showing in full lines the cross-sectional shape of a belt according to the present inven- 15 tion, and showing in dotted lines on an exaggerated scale the tendency of an ordinary rubher belt to bulge laterally and flex about its central region as the result of longitudinal compression in the rubber component of the belt;

2 Fig. 2 is a side view of the whole belt of Fig. I

Fig. 6 is a side view of a separately constructed elastic rubber annulus adapted to be combined with the backing element of Fig.

I 35 Fig. 7 is a side view of the backing element and annulus of Figs. 5 and 6 combined on a mandrel by stretching. the annulus about the backing;

Fig. '8 isa side view of a rigid backing element .in the form of a cylinder; 4 Fig. 9 is a side view of the corresponding rubber annulus;

Fig. 10 is a side view of the web-compressing member resulting from stretching the annulus of Fig. 9 about the cylinder of Fig. 8;

45 Fig. 11 is a fragmentary side view of a belt adapted to be stretched to the shape and size of the belt in the machine of Fig. 1;

Fig. 12 is a diagrammatic side view illustrative of one method of forming the belt of the ma- 50 chine;

Fig. 13 is a view similar to Fig. 1 showing a modification;

Fig. 14 is a diagrammatic view of the belt of Fig. 13 on a mandrel during its manufacture;

55 Figs. 15 and 16 are fragmentary diagrammatic views on a larger scale than Fig. 14, showing stages in making the belt of Fig.- 13; and' Fig. 17 is a diagrammatic view on a scale similar to that of Figs. 15 and 16, showing a frag:

60 ment of thebelt of Fig. 13.

In the illustrated machine for compressively shrinking a textile web, the web-compressing member is shown in the form of a belt Ill comprising a flexible but relatively inelastic backing 65 element II and an elastic element. 12 of which the free surfaceis caused to contract and compressively shorten the cloth web W. The backing element II 'is for example formed of layers of. canvas or other fabric built up and strength- 70 ened by vulcanized rubber intimately associated therewith. The thicker elastic element I2 is preferably formed of rubber vulcanized to a degree of hardness and elasticity appropriate to the desired amount of pressure and contracting ac- 76 tion to which the belt surface is subjected.

As indicated in Fig. 1, the belt I0, with its elastic rubber portion l2 outermost, is conveyed around rolls l5 and it, either of which may be driven by appropriate connections not shown. A rubber roll I1 is located in position to nip or 5 press the belt it against the roll ii at the point of departure of the belt therefrom, and to define a path of subsequent belt travel having a curvature opposite to the part of-the path defined by roll I5. Thus the operative surface of belt l2 10 is convex as it receives the web W and passes over roll l5, but becomes concave in passing around roll II. This alteration in curvature from convex to concave contracts the web-engaging surface. i2 of the thick belt, and the shrinking 16 of the fabric web W takes place as the web is confined by the roll ll to this contracting webengaging surface.

I have found that'the various above-described difliculties attendant upon the use of an elastic 0 web-compressing member, such for example 'as the belt of British Patent No. 402,087, can be avoided by providing the machine with a webcompressing member of which the material forining the operative or web-engaging surface thereof can attain its concave shape or otherwise contract to shrink the web without at the same'time assuming a substantially compressed condltion.

Thus in manufacturing the belt I0 01' this application I prefer to impart to the thick rubber portion I! an initial tension which will tend to cause contraction of the operative surface. of the belt. For example, a short length of the belt, cutoff from the remainder thereof perpendicular to the backing element II, and relaxed as much as'possible, is shown in Fig. 3 as having assumed naturally a concave shape of its web-engagingsurface l2 and as having a shorter length of elastic webengaglng surface ii than'of inelastic backing element II. This will permit the web-engaging 40 surface of the belt to assume a concave shape at the appropriate place 'in the machine without the creation of substantial endwise compressive forces within the rubber l2, and hence avoid the surface distortions of the belt and fabric mentioned above.

This result can be obtained by a'number of specific ways of manfacturing the belt. For ex-. ample, if it is desired to form the belt about a circular mandrel I! such as indicated in Fig. 4, the thick rubber. portion l2 can be applied to the mandrel first, with the web engaglng sur-' face 12 innermost, the composite fabric and rubber backing element ll applied to the larger outside periphery of the rubber element I2 and fastened thereto, and the whole belt then re-' moved from the mandrel and turned inside out into the form shown in Fig. 3. This stretches the elastic rubber annulus l2 over the backing member II so as to put the outer surface I! of the body in tension such that it will tend to assume a shorter length than the backing element when possible.

By a comparison of Figs. 2 and 4, it will be seen that the arc ab of the web-engaging surface l2 of the belt in Fig. 4 has become stretched to the longer are ab' when the belt is turned inside out into the form of Fig. 2. The curvature of the short section of belt in Fig. 3 represents the return of the stretched longer are a'b' of the belt of Fig. 2 to its initially shorter arc a-b when this section of belt is allowed to relax.

Many other ways of imparting such initial tension to the rubber portion 12 -durin manufacture of the belt will be apparent. For exampla'if it is desired to build the backing ele ment and the rubber portion I2 separately in circular form and cement them together, the rubber portion l2 merely need be made of smaller initial diameter so that when stretched over the backing element II the rubber portion I2 is under tension.

Thus Fig. 5 illustrates a mandrel l9 having the inelastic backing member ll formed about it; Fig. 6 shows the corresponding separately formed rubberannulus I! having in its unstressed state a smaller diameter or peripheral length than the combined mandrel and backing member H, and Fig. '7 shows the annulus l2 stretched about the backing member I i and cemented thereto.

A third way of making the belt is to form the rubber portion l2 in circular form, turn it inside out, form the inelastic backing member II on a mandrel, and stretch theinside-out rubber portion I! over the backing member II and cement the two together.

A fourth specific way of making the belt by stretching the elastic member over its backing element is to make the rubber portion l2 in annular form, elongate this portion on a pair of rollers 25, 26 suitably held apart, and while the rubber is thus stretched, apply and cement the relatively non-stretchable fabric portion l i 'to the interior surface of the stretched rubber annulus,

as indicated in Fig. 12.

A modification of this fourth way of .making the belt includes the preliminary step of turning the separately formed rubber portion l2 inside out before further stretching it on rollers and applying the fabric portion thereto as described above.

According to a sixth way of stretching the material of the elastic member over its backing element, the relatively inextensible portion II can be placed on rolls or on a mandrel such as indicated at IS in Fig. 5, and the rubber element l2 built up thereon by winding on strips of properly vulcanized rubber, stretched under the proper tension until the belt has the appropriate thickness, and securing this stretched rubber in place.

The above six ways of making the web-compressing member result in forming a belt in which the desired degree of tension is inherent in the rubber adjacent to the web-engaging surface. It is also possible for such inherent tension to be replaced or supplemented by tension which is set upin the rubber by the shrinking machine into which the belt is placed. For example, instead of the belt ll! of Fig. 1 having the initial cir-' cumferential length of the belt shown therein, the belt can be made initially smaller, for example about twenty per cent less in circumferential length, as indicated by the diameter of the belt in the fragmentary view of Fig. 11, and be stretched in the shrinking machine to the form shown in Fig. 1. In this case, the backing element I I, while less extensible than the rubber element l2, should be sufficiently elastic to permit the belt to be stretched sufliciently to bring the rubber portion to such state of tension that the rubber is not underendwise compression at it's place of longitudinal contraction in passing around roll II. The relatively inextensible backing element ll of this belt of Fig. 11 may for example be a loosely woven rubber-filled fabric adapted to limit the stretch of the belt as a whole to say twenty-five per cent of its .at-rest length. This belt can be 'made by building the partially elastic element II and covering it in the regular way with the rubber element l2, the rubber of both portions of the belt being properly vulcanized.

A preferred form of machine, otherwise resembling the machine of Fig. 1, is provided with a belt which is substantially stretched from its at-rest length to a point at which further stretch of the belt as a whole is limited by the tightening of initially loose or slackened longitudinal or warp elements, which can form either a backing or an internal strengthening member. Referring to Fig. 13, the belt of that figure is shown as substantially stretched to such limiting point from its initial smaller size corresponding to the diameter of the mandrel IQ of Fig. 14. A preferred way of making this belt is to build up on the mandrel l9 sufficient rubber to form an inner layer l2, then apply a layer of strong fabric which has been woven or shrunk in such manner that it can be stretched say twenty per cent. to a limiting point where it becomes relatively inextensible, and then build up on the textile fabric a further layer of rubber l2 Fig. 15 shows these layers diagrammatically on a larger scale than Fig. 14. Instead of a single such fabric layer, a plurality of such fabric layers may be employed, preferably with thin rubber layers between them. The whole is then vulcanized in this relatively small state and approximately at-rest length, and the rubber layers thus consolidated and bonded with the fabric, as indicated in Fig. 16. Figs. 15 and 16 show diagrammatically an exaggerated curvature of the warp yarns l I, indicative 'of their ability to permit a substantial stretch of the belt as a whole to an extent such that these warp yarns become nearly straight, and Fig. 1'7 shows diagrammatically a short straight section of the belt in its stretched condition in the shrinking machine of Fig. 13. In this machine, as in the other forms of the invention,the elastic material adjacent to the web-engaging surface is under sumcient tension, prior to contracting, to prevent compression of such material during the contraction in which the web is shrunk.

It may be desirable to grind the outer webengaging surface of the web-compressing ele ment until it is true, if any surface inequalities are found to be present.

The present invention is also applicable to processes of mechanical shrinking in which the web-carrying surface is distorted by means other than or in addition to a change in curvature of the surface. For example, referring to Fig. 1 or to Fig. 17, a greater amount of shrinking can be obtained if the driving connections for roll I! are such as to drive this roll at a greater speed than the belt. The roll I! then applies a surface friction to the belt through the intermediary of the web W such as to force the surface portion of the belt material in a forward direction at the entrance to the nip between the belt and roll l1, thus creating a difierential between the surface speed of the rubber at the entrance to the nip and the surface speed at the exit to the nip. In this case, the shortening of the belt surface by the distorting effect of the frictionally acting roll ll involves relieving the inherent tension existing in the rubber l2. This inherent tension is thus useful in permitting a substantial amount of shortening of the rubber to take place without evenness of its surfice.

' having the general outward form of the belt of British Patent No. 402,087, comprising elastic rubber. and a flexible backing element, it will readily be apparent how the invention is to be applied in similar manner to a rubber element having a rigid backing member, such for example as in the case of the rubber element of British Patent No. 400,950 of which the backing element is a metal roll forming the interior thereof. As will be observed from that patent, the rubber element constitutes a deformable covering for its associated backing roll, and this deformable covering is adapted to be locally distorted to a concave shape and subjected to a local contracting action by the frictional action of a cooperating pressure roll run at a faster speed than the speed of the rubber element.

In Figs. 8 and 10, the reference character 20 indicates a heavy metal roll such as employed in British Patent No. 400,950 as the backing member or support for the rubber web-compressing element by which it is covered. Fig. 9 illustrates the annulus I2 of initially smaller diameter than the roll 20, and Fig. 10 shows the completed web-compressing member formed by stretching the smaller annulus I! about the roll 20, thus to create an inherent strong tension in the rubber material.

The above British patents may be referred to a for the details of construction of the shrinking machine of Fig. 1 aside from the web-compressing member described above, or for the details of construction of a shrinking machine adapted to employ the web-compressing member of Fig. 10 of this application. However, by the present invention, such machines can be made smaller duce about fifty per cent. more mechanical shrinkage than when equipped with a normally constructed but somewhat thicker belt. The present invention therefore permits the thickness of the belt to be decreased.

Moreover, by use of an inherent'tensionin the rubber to or eliminate compression in the rubber, the belt is caused tov hug the upper roller l1 naturallywithout the application of a high tension to the backing element of the belt when the belt is in the machine. Accordingly since the machine is subjected to less strain, it can be made lighter, and the rolls can be made smaller without bending. This decrease in size of rolls in turn permits a shorter length of belt to be used. Moreover, since the amount of effective surface contraction of the belt is increased by decrease in the size of the rolls, the amount of shrinking is further increased by this means, or if desired, a thinner belt can be used to obtain a desired amount of shrinking.

As suggested above, a machine according to the present invention has a more uniform shrinking action than prior 'machines employing elastic web-compressing members. The tendency of such machines to shrink the middle portions of the web more than the selvedges, is avoided, and the finished web is as flat and thoroughly shrunk at its selvedges as at its middle. The avoidance of substantial compression within the elastic material adjacent .to the web-compressing member prevents puckering and accordingly prevents the formation of ridge-like imperfections in the web. Moreover, this avoidance of compression prevents such sidewise motion of the surface portions ofthe web-compressing member as has previously tended to displace the warps of the web into wavy lines in certain types of fabrics. The present invention is therefore particularly valuable in the shrinking of certain fabrics, such as rayons, which offer more than the average resistance to compressive shrinking action, especially in weave structures, such as twill, in which the warps are not anchored at each filling thread. Such fabrics which ordinarily tend to exhibit warps which are wavy or irregular in plan view when compressively shrunk a large amount, can be shrunk by use of the present invention to an extent not heretofore practical.

I claim:

1. A machine for shrinking a cloth web, including an elastic member of which a web-engaging surface is adapted to contract and has a path such that it forms a concave surface, and means for pressing the web against the concave contracting surface of said member, the elastic material adjacent to the web-engaging surface of said member being under sufficient tension in the machine prior to said contraction to prevent compression of said material in the direction of the contraction during said contraction.

'2. A machine for shrinking a cloth web, including an elastic member of which a web-engaging surface is adapted to contract, and means for pressing the web against a contracting surface of said member, said elastic member having as manufactured a suillcient inherent tension in its elastic material adjacent to its web-engaging surface to prevent compression of said material in the direction of the contraction during said contraction.

3. A machine for shrinking a cloth web, including an elastic member of which a surface is adapted to contract, and means for pressing the web against saidcontracting surface, said elastic member having as manufactured an inherent tension in its elastic material adjacent to the web-contracting surface thereof.

4. A machine for shrinking a cloth web, including a web-carrying belt, and means for establishing a path of travel of the belt in which the web-contracting surface of the belt flexes from a convex to a concave shape and so contracts, the web-contracting portion of the belt being of elastic material under sufficient tension in the convex shape to avoid substantial internal compression in the direction of the contraction in flexure to the concave shape.

5. A machine for shrinking a cloth web, including an elastic web-engaging member of which the surface is adapted to contract, and means for distorting the web-engaging member to shrink the web, said member having as manufactured an inherent tension adapted to be relieved by the distorting action of said means.

6. A machine for shrinking a cloth web, including a moving web-engaging member of elastic material of which the surfaceis adapted to contract, and means for locally advancing the surface portion of said member ahead of underlying portions thereof thereby to cause a subsequent recoil of the surface portion adapted to shrink the web, the said elastic material adjacent to the web-engaging surface of said element being under such tension as to prevent the said local advancement from causing compression of the elastic material sufficient to cause unevenness of the surface thereof.

-'7. A machine for shrinking a cloth web, including a moving web-engaging member of elastic material of which the surface is adapted to be contracted, and means for applying surface friction to said moving member to cause elongation and contraction of said material at the webengaging surface, said member having an inherent tension in its elastic material at the webengaging surface suflicient to allow said contraction thereof without the production of acorresponding amount of compression in said material sufficient to create unevenness of its web-engaging surface.

8. A machine for shrinking a cloth web, including an elastic member of which a surface is adapted to contract, and means for pressing the web against said contracting surface, said elastic member including a relatively inelastic backing element coextensive therewith, and the contracting surface of said elastic member having in its unstressed state a shorter length than the said backing element. g

9. A machine for shrinking a cloth web, including an elastic web-carrying belt, means for establishing an endlem path of travel of the belt in which the web-contacting surface of the belt contracts and assumes a concave shape, including means for holding the web against the contracting surface of the belt, the belt as a whole being substantially elongated from its atrest length and the web-contacting surface portion thereof being sufficiently stretched to prevent substantial internal compression of its material in the direction of the contraction in assuming said concave shape.

10. A machine for shrinking a cloth web, including an elastic web-carrying belt, means for establishing an endless path of travel of the belt in which the web-contacting surface of the belt contracts and assumes a concave shape, including means for holding the web against the contracting surface of the belt, the belt as a whole being substantially elongated from its atrest length and the web-contacting surface portion thereof being suficiently stretched to prevent substantial internal compression of its material in the direction of the contraction in assuming said concave shape, the belt including a longitudinal element which in the stretched state is strongly resistant to further elongation.

11. A machine for shrinking a cloth web, including an elastic web-carrying belt, means for establishing an endless path of travel of the belt in which the web-contacting surface of the belt (iontractsand assumes a concave shape, including means for holding the web against thecontracting surface of the belt, the belt as a whole being substantially elongated from its at-rest length and the web-contacting surface portion thereof being sufficiently stretched to prevent substantial internal compression of its material in the direction of the contraction in assuming said concave shape, the belt includinga textile element adapted to be elongated relatively easily from the at-rest state of the belt to said stretched state, and thereupon oifer strong resistance to further extension. 7

12. A machine for shrinking a cloth web, including an elastic web-carrying belt, means for establishing an endless path of travel of the belt in which the web-contacting surface of the belt contracts and assumes a concave shape, in-

cluding means for holding the web against the contracting surface of the belt, the belt as a whole being substantially elongated from its at-rest' length and the web-contacting surface portion thereof being suiiiciently stretched to prevent substantial internal compression of itsmaterial in the direction of the contraction in assuming said concave shape, the belt including a textile element having warps lying in a relatively relaxed state in the at-rest condition of the belt and offering strong resistance to further extension of the belt from said stretched condition.

13. A machine for shrinking a cloth web, including an elastic web-carrying belt, means for establishing an endless path of travel of the belt in which the web-contacting surface of the belt contracts and assumes a concave shape, including means for holdingthe web against the contracting surface of the belt, the belt as a whole being substantially elongated from its atrest length and the web-contacting surface portion thereof being sufflciently stretched to prevent substantial internal compression of its material in the direction of the contraction in assuming said concave shape, the belt comprising a layer of textile material and outer layers of rubber, the textile material being adapted to limit the elongation of the belt in said stretchedcondition.

14. A web-compressing member for use in a machine for shrinking textile Webs, said member including a body of elastic material having a surface adapted to contact and shrink the web and adapted to be distorted during action of the said web-compressing member in the machine, and a relatively inelastic portion, the web-compressing member having the web-contacting portions of its elastic material sufliciently stretched with respect to the inelastic portion so that in thedistortion of the elastic material in the machine an inherent tension in said webcontacting portions of elastic material prevents said web-contacting portions from coming under any substantial longitudinal compression during the shrinking.

15. A belt adapted for use in a machine for shrinking textile webs, said belt including a body of elastic material having a surface adapted to contact and shrink the web and adapted to be distorted during action of the said web-compressing member in the machine, and a relatively inelastic portion, the belt having the web-contacting portions of its elastic material sumciently stretched with respect to the inelastic, portion so that in the distortion of the elastic material in the machine an inherent tension in said web-contacting portions of elastic material prevents said web-contacting portions from coming under any substantial longitudinal compression during the shrinking.

16. A belt adapted for use in a machine for shrinking textile webs, said belt including a body of elastic material having a surface adapted to contact the web, and a relatively inelastic portion, the web-contacting surface portions of the elastic material being stretched sufficiently with respect to the inelastic portion to create in the belt an inherent tension in its elastic material effective to cause the web-contacting surface to become concave in the direction of length of the belt in the case of a short section of the belt cut oil and allowed to relax.

17. A web-compressing member for use in a machine for shrinking textile webs, said member including, a body of elastic material adapted to respond to surface friction by stretching and shortening of adjacent portions of the web-contacting surface of the member, said member having as manufactured an inherent tension in its elastic material adapted to permit substantial contraction or the web-contacting surface portions of the elastic material in a concave conditionwithout the said portions coming under any 10 substantial compression in the direction of their contraction.

' 18. A belt adapted for use in a machineior compressively shrinking textile webs, said belt including a body or elastic material adapted to 15 respond to surface friction by stretching and shortening of adjacent portions of the web-contactingsurface of the belt, said belt having as manufactured an inherent tension in its elastic material adapted to permit substantial contrac-' tion of the web-contacting surface portions of the elastic material in a concave condition without the said portions coming under any substantial compression in the direction of their contraction. 19. A belt adapted for use in a machine for shrinking textile webs, said belt. including an annular body of elastic material having an outer surface adapted to contact the web, and an inner portion affording a greater resistance to longitudinal extension than the said elastic material while permitting the belt to be elongated as a whole by stretching to such extent that when thus stretched the belt can be flexed. to form a concavity in the outer surface of the belt without compressing the elastic material thereat.

SANFORD L. CLUEII'. 

